Fig 1.
Biomass flow transfers between a prey and a predator.
Black arrows represent energy transfers or losses. The prey has a trophic level τ and the predator has a trophic level (τ+1). Fishing mortality F and natural mortality M0 represent non-predation mortalities. Excretion U and respiration R are the predator metabolic losses. The partial transfer efficiency (Pτ+1/Qτ+1) and total transfer efficiency (Pτ+1/Pτ) are indicated (derived from Gascuel et al.,[39]).
Fig 2.
Examples of trophic spectra for the North Sea large marine ecosystem.
(a) Catch Spectrum in 1970 where each colored area represents a smoothed species-specific catch; (b) Catch trophic spectrum, where each curve represent the mean spectrum over 5 years; light grey to black lines from 1951–1955 to 2006–2010 (c) Speed of flows P/B spectrum from 1951 to 2010 (d) Partial transfer efficiency P/Q trophic spectrum from 1951 to 2010.
Fig 3.
Worldwide values and trends of transfer efficiency, residence time, fishing and climate indicators.
(a) Mean 1950–2010 values of the Time Cumulated Indicator TCI per type of ecosystem (in years); (b) Mean 1950–2010 values of the Efficiency Cumulated Indicator ECI per type of ecosystem; (c) Worldwide trend in TCI; (d) Worldwide trend in ECI; (e) Worldwide SST anomaly relative to the mean of the time-series (orange, in °C, left axis) and O2 anomaly trends (yellow, in mol O2 m-3, right axis) (f) Worldwide trends in the fishing pressures indices: SSP (red, in % on the left axis) and Lindex (orange, right axis); (g) Shannon index (h) Percent of fish species. Colored sectors refer to bootstrap confidence intervals of the mean of LMEs, at 95%.
Fig 4.
TCI and ECI trends on an a priori selection of LMEs.
(a) Time indicator nominal values trends (b) Efficiency indicator nominal values trends–‘Group 1’ gathers the 10 most strongly exploited ecosystems (according to their SSPs); ‘Group 2’ gathers the 10 ecosystems with the strongest increase in SST since 1990; ‘All LMEs’ gathers the 56 LMEs. Colored sectors refer to bootstrap confidence intervals of the mean, at 95%.
Fig 5.
Results from the Principle Component Analysis and clustering on the Time Cumulated Indicator TCIR.
(a) Worldwide map of the clusters; Mean trend per cluster from 1950 to 2010 in: (b) Relative to 1950 TCIR (colored sectors refer to bootstrap 95% confidence intervals); (c) Nominal values of TCI; (d) Number of overexploited and collapsed stocks in SSPs (%); (e) FiB index; (f) the Mean Trophic Level; (g) the Shannon biodiversity index.
Table 1.
Clustering based on trends in the Time Cumulated Indicator (TCIR) and the Efficiency Cumulated Indicator (ECIR): Selection of results regarding clusters description by supplementary qualitative variables.
Fig 6.
Results from the Principal Component Analysis and clustering on the ECIR.
(a) Worldwide map of the clusters; Mean trend per cluster from 1950 to 2010 in: (b) Relative to 1950 ECIR (colored sectors refer to bootstrap 95% confidence intervals); (c) ECI nominal values; (d) Lindex of fishing pressure; (e) Difference SST(y)−SST(1950); (f) the Shannon biodiversity index (g) Fraction of finfish species (%).